Get an object scanned for use in blender
There are many different programs available for 3D Scanning. I think these are probably the best (give highest quality results) and are the easiest to use. 


RealityCapture, great for huge environments taken from drones but it's very expensive.
Agisoft Photoscan, probably the best value imo but still a tad expensive
Meshroom, free on github, I've had pretty good results with this
123D Catch, rubbish results but free and very easy to use. I have a feeling it's been discontinued tho.


All of these can export the mesh as .OBJ I think, blender can import this. Be prepared for a slow experience though, 3D scans can have millions of poly's.

You'll need a decent camera to take photographs of your object, a modern phone camera will probably work ok but a DSLR will be preferable. When you take photos make sure there is plenty of overlap between images.

To get the best results either make use of lighting equipment indoors to create an even lighting environment, or wait until an overcast day comes and go outside. Never 3D scan on a bright sunny day as you'll have very harsh shadows which will be 3D scanned and then you'll have a permanent shadow in blender.

It should be noted that you cannot 3D scan (with photogrammetry anyway) transparent or reflective surfaces as the software cannot determine which is the object and which is a reflection, you'll get nasty artifacts.

Once you've imported into blender you'll probably want to use the decimate modifier set to between 0.05 and 0.5 depending on how detailed you want the final mesh to be. In my experience I can set it to as low as  0.1 and not even lose any detail while reducing the number of verts by 90%.

If you want to get fancy, then you could retopologize the mesh and bake the normals from the high density mesh to the retopologized mesh.

CG Geek has a good tutorial on using meshroom. Gleb also has a few tutorials on 3d Scanning: Photoscan, 123D Catch, Visual SFM and Meshlab.